I. Field of the Invention
The present invention relates to a machine for cutting a workpiece made of styrofoam or like material.
II. Description of the Prior Art
Forms made of styrofoam or similar material are frequently used in casting operations. Such forms are typically cut in the shape of the desired casting and the mold material, typically green sand, is then applied to the outside of the styrofoam form. The styrofoam form is then liquified by heating and removed from the sand mold. After its removal, the sand mold is filled with the molten metal in the conventional fashion thus forming the casting.
It has been the previous practice to construct the styrofoam forms by hand cutting the styrofoam from styrofoam blocks. For large castings, multiple blocks are individually cut and the resulting forms are then laminated together to form the final styrofoam form.
The previously known method of hand cutting the styrofoam forms to the desired shape, however, suffers from a number of disadvantages. One disadvantage is that, as in all hand operations, it is virtually impossible to obtain high accuracy of the final styrofoam form. Such inaccuracies in cutting the styrofoam form by hand may require additional machining of the final casting.
A still further disadvantage of cutting the styrofoam form by hand is that measuring and layout errors can and do occur. Depending upon the magnitude of such errors, destruction of the styrofoam form may be necessary.
A still further disadvantage of hand cutting styrofoam forms is that the hand tools used to cut the styrofoam can only obtain a relatively rough cut of the styrofoam. This rough cut results from the cellular or bead nature of the styrofoam so that, when hand cutting occurs, the beads or cells of the styrofoam pull away from the styrofoam block and leave a rough surface. Such a rough surface will cause a correspondingly rough surface on the sand mold and a like rough surface on the finished casting. Such rough surfaces disadvantageously increase the amount of machining required for the final cast iron part.